Mathematical modeling of the Fontan blood circulation supported with pediatric ventricular assist device.

The decompensated univentricular circulation is identified as one of the most challenging conditions and the application of the mechanical circulatory support (MCS) devices is proposed as therapeutic option for Fontan failure. Modelling methodologies are reported to identify the optimized types, extent and duration of required hemodynamic support using MCS. The specific parameters of device-body interaction during support of failing Fontan circulation within the design points of dedicated pediatric ventricular assist devices has not been previously defined. In this work, we introduce a mathematical model developed to simulate the interaction between the Fontan single-ventricular circulation and a constant-flow pediatric ventricular assist device (VAD) Sputnik. The interaction is studied at a pump rotor speed of 5000-9000 rpm. This simulation demonstrates that the pump replacing pulmonary ventricle of the heart creates necessary pressure differential between the systemic veins (7 mmHg) and the pulmonary artery (17.3 mmHg). Moreover, it increases the venous return that, according to the Frank-Starling mechanism, increases the stroke volume up to 32 ml/bpm (26 ml/bpm - without using a pump). For the first time, a simulation for the pediatric VAD Sputnik has been carried out. The simulation results confirm pediatric VAD Sputnik can be a possible tool to normalize the Fontan circulation in pediatric patients.